Microwave-assisted peanut oil extraction process with nutrition retention

Abstract

The present application belongs to the technical field of vegetable oil processing, and particularly relates to a microwave-assisted peanut oil extraction process for retaining nutrients. The peanut oil extraction process comprises the steps of raw material screening, multi-stage microwave-assisted pretreatment, conditioning pretreatment, pressing and refining. The method can improve the oil yield while retaining the natural nutrients such as vitamin E and phytosterol in peanut oil to the maximum extent. The process has the characteristics of high oil extraction efficiency, good nutrient retention, strong oil stability and high safety, and is suitable for industrial application.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of processing of plant oil, and particularly relates to a microwave-assisted peanut oil extraction process for retaining nutrients. BACKGROUND

[0002] The information disclosed in this Background section is only for the purpose of increasing an understanding of the general context of the application and does not necessarily constitute an admission that this information forms part of the prior art that is already known in this field.

[0003] Peanut oil, as one of the main plant oils consumed by Chinese residents in daily life, is rich in unsaturated fatty acids, vitamin E, phytosterols and other nutrients beneficial to human body, and its nutritional value and flavor quality are of great concern

[0004] At present, the traditional peanut oil extraction process mainly includes pressing method and leaching method. The pressing method separates oil from peanut kernels through physical extrusion. Although this process can retain some natural nutrients in oil to some extent, it has the following shortcomings: high-temperature roasting of peanut kernels is required in the pressing process to improve the oil yield, but high temperature can easily lead to the destruction of heat-sensitive nutrients (such as vitamin E) and may cause oil oxidation, affecting its nutritional value and shelf life.

[0005] The leaching method uses organic solvents to extract oil, which can achieve a high oil yield, but the residual risk of organic solvents and the loss of nutrients during the extraction process are more prominent, and complex desolventization and refining processes are required subsequently, which not only increases the production cost, but also may further loss of effective nutrients in oil.

[0006] In order to improve the defects of traditional process, some auxiliary oil extraction methods have appeared in the prior art, such as ultrasonic-assisted, enzyme-assisted, etc.

[0007] Chinese patent CN105219523A discloses a method for microwave-assisted low-temperature pressing of celery seed oil. The method uses celery seeds with a moisture content of 4-6% as raw material. After microwave treatment, the oil is pressed at a temperature of 55-65℃. After centrifugation and filtration through three layers of gauze, the volatile components and other fat-soluble nutrients (such as vitamins E and A) of the celery seed oil are retained to the maximum extent. Chinese Patent Publication No. CN110791366A discloses a method for preparing high-quality, high-oleic peanut oil, comprising the following steps: Step 1, mixing 85-99 parts by weight of high-oleic peanut oil with 1-15 parts by weight of selenium-enriched peanut oil and then microwave-treating the mixture to obtain mixture 1; Step 2, mixing 1-14 parts by weight of selenium-enriched camellia root powder with 86-99 parts by weight of mixture 1 to obtain mixture 2; Step 3, pressing mixture 2 in an oil press to obtain crude oil; Step 4, filtering the crude oil until it is clear and transparent to obtain high-oleic peanut oil.

[0008] However, the cavitation effect and mechanical vibration of ultrasound can generate localized high temperatures, which can easily lead to the oxidation of unsaturated fatty acids and the destruction of active ingredients such as vitamins in oils, affecting the nutrition and flavor of the oils. Prolonged or high-intensity ultrasonic treatment can increase the content of free fatty acids in oils, reducing their stability and shortening their shelf life.

[0009] Therefore, how to improve the oil yield of peanut oil while preserving its natural nutrients to the greatest extent has become a pressing technical problem to be solved in the current peanut oil processing industry. Summary of the Invention

[0010] This invention aims to provide a microwave-assisted peanut oil extraction process for nutrient retention. This process, through multi-stage microwave directional control and precise process coordination, improves oil yield while preserving the natural nutrients in peanut oil. Specifically, it includes the following steps:

[0011] Raw material selection and initial processing

[0012] Select high-quality peanut kernels with an oil content of 50%~55% and a moisture content of 8%~10%. Remove impurities, broken kernels and moldy kernels by passing them through a vibrating screen (screen hole diameter 2~3mm) to obtain pure peanut raw materials for later use.

[0013] Microwave-assisted preprocessing

[0014] Through multi-stage, irregular gradient regulation, targeted modification of cell structure is achieved while shortening the total time, taking into account both lipid release efficiency and nutrient protection.

[0015] Phase 1:

[0016] Parameters: Microwave frequency 2450MHz, power 280~320W, processing time 60~90 seconds.

[0017] Phase 2:

[0018] Parameters: Microwave frequency 2450MHz, power 320~380W, processing time 90~120 seconds.

[0019] Phase 3:

[0020] Parameters: Aqueous substances: 0.2%~0.5% (w / v) food-grade citric acid solution;

[0021] Spraying amount: Precisely control according to 0.4%~0.8% of the raw material mass (i.e., spray 0.4~0.8L of solution per 100kg of peanuts).

[0022] Operating method: Use a dual-fluid atomizing nozzle (atomizing particle size 30~50μm) to spray evenly, ensuring that the peanut surface coverage is ≥90%;

[0023] Standing time: After spraying, let stand for 30-45 seconds, and maintain the moisture content of the raw material at 8%-10% (monitored in real time by an online near-infrared detector; if the moisture content exceeds the standard, it can be finely adjusted by 20-30 seconds with hot air at 30-40℃).

[0024] Phase 4:

[0025] Parameters: Microwave frequency 2450MHz, power 420~480W, processing time 80~120 seconds (microwave 20 seconds interval 5 seconds, excluding interval time).

[0026] Phase 5:

[0027] Parameters: Microwave frequency 2450MHz, power 290~340W, processing time 30~60 seconds; after processing, keep warm and stand still for 90 seconds.

[0028] Conditioning and pretreatment

[0029] After multi-stage microwave treatment, peanuts are sent to a conditioning equipment. The moisture content of the peanuts is precisely adjusted to 11%~13% by spray humidification or hot air temperature control, and the temperature is controlled at 40~50℃. The peanuts are kept warm and left to stand for 10~15 minutes to make the physical state (hardness, plasticity) of the peanuts suitable for the subsequent pressing process.

[0030] High-efficiency pressing

[0031] It adopts a hydraulic high-efficiency pressing equipment, with a pressing temperature of 70~90℃, a pressing pressure of 15~20MPa, and a pressing time of 20~30 minutes.

[0032] Refining

[0033] Through a physical refining process of "degumming → deacidification → decolorization → deodorization," impurities are removed at low temperatures, while maximizing nutrient retention.

[0034] (1) Degumming process

[0035] Add 85% phosphoric acid (0.1%~0.3% of the oil weight) to the crude oil, stir at 50~60℃ for 30 minutes, and then separate the gums by disc centrifuge (8000~10000r / min), with a removal rate of ≥95%.

[0036] (2) Deacidification process

[0037] The degummed oil is fed into the deacidification tower, and the temperature is controlled at 100~120℃ and the vacuum degree is 0.09~0.095MPa. Superheated steam (150~180℃) is introduced for 30~45 minutes. Free fatty acids are removed by steam distillation, and the acid value (calculated as KOH) is reduced to ≤0.5mg / g.

[0038] (3) Decolorization process

[0039] Add a mixed adsorbent of attapulgite clay (1.5%~3%) and composite activated carbon (0.5%~1%) to the deacidified oil, and stir for 20~30 minutes at 80~90℃ and vacuum degree 0.08~0.09MPa to adsorb pigments and trace impurities; then remove the adsorbent by passing it through a plate and frame filter (filtration pressure 0.3~0.5MPa), and the oil color (Lovibond colorimeter 133.4mm) reaches yellow 25~30 and red ≤2.

[0040] (4) Deodorization process

[0041] Deodorization is assisted by molecular distillation at 130-150℃ for 20-30 minutes, followed by short-path distillation (200℃ / 0.1Pa) for 2-5 minutes.

[0042] Compared with the prior art, the technical advantages of the present invention are as follows:

[0043] Compared with the prior art, the present invention has the following significant technical effects:

[0044] (1) Oil yield significantly increased

[0045] This invention achieves an oil extraction rate of 45.3% to 47.5% through multi-stage microwave directional control and citric acid-assisted treatment, which is significantly higher than the experimental group data.

[0046] (2) High efficiency in preserving natural nutrients

[0047] The peanut oil prepared by this invention retains 49.4~51.2 mg / 100g of vitamin E, which is much higher than that of the control group (34.6~45.7 mg / 100g), and the phytosterol content is maintained at 85.0~87.6 mg / 100g. Attached Figure Description

[0048] Figure 1 Examples 1-3: Comparison of oil extraction rates in each experimental group.

[0049] Figure 2 Examples 1-3: Comparison of phytosterol content in peanut oil of each experimental group.

[0050] Figure 3 Examples 1-3: Comparison of vitamin E content in peanut oil of each experimental group. Detailed Implementation

[0051] To make the objectives and technical solutions of this invention clearer, the following embodiments are provided for further explanation. However, the scope of protection of this invention is not limited to these embodiments; the embodiments are merely for illustrative purposes. Those skilled in the art should understand that any changes or equivalent substitutions that do not depart from the concept of this invention are included within the scope of protection of this invention.

[0052] Example 1: Microwave-assisted peanut oil extraction process

[0053] (1) Raw material selection and initial treatment: Select high-quality peanut kernels with an oil content of 50%~55% and a moisture content of 8%~10%, peel them, and remove impurities, broken kernels and moldy kernels by vibrating screen (screen hole diameter 2~3mm) to obtain pure peanut raw materials for use.

[0054] (2) Microwave-assisted pretreatment

[0055] Phase a: Microwave frequency 2450MHz, power 300W, processing time 75 seconds.

[0056] Phase b: Microwave frequency 2450MHz, power 350W, processing time 105 seconds.

[0057] Stage c: Aqueous substance: 0.35% (w / v) food-grade citric acid solution; Spraying amount: precisely controlled at 0.6% of the raw material mass; Operation method: uniformly spray using a dual-fluid atomizing nozzle (atomizing particle size 40μm) to ensure peanut surface coverage ≥90%; after spraying, let stand for 40 seconds, maintaining the raw material moisture content at 8%~10% (monitored in real time by an online near-infrared detector; if the content exceeds the standard, it can be finely adjusted for 20~30 seconds with 30~40℃ hot air).

[0058] Stage d: Microwave frequency 2450MHz, power 450W, processing time 100 seconds (microwave 20 seconds interval 5 seconds).

[0059] Stage e: Microwave frequency 2450MHz, power 320W, processing time 45 seconds; after processing, keep warm and stand still for 90 seconds.

[0060] (3) Conditioning and pretreatment: After multi-stage microwave treatment, peanuts are sent to conditioning equipment. The moisture content of peanuts is adjusted to 11%~13% by spray humidification or hot air temperature control, and the temperature is controlled at 40~50℃. The peanuts are kept warm and left to stand for 10~15 minutes.

[0061] (4) High-efficiency pressing: The hydraulic high-efficiency pressing equipment is adopted, with the pressing temperature set at 80℃, the pressing pressure at 20MPa, and the pressing time at 25 minutes.

[0062] (5) Refining

[0063] Degumming process: Add 85% phosphoric acid (0.2% by weight of oil) to the crude oil, stir at 55℃ for 30 minutes, and then separate the gums using a disc centrifuge (9000 r / min), with a removal rate ≥95%. Deacidification process: Send the degummed oil into a deacidification tower, control the temperature at 110℃ and the vacuum at 0.09~0.095 MPa, and introduce superheated steam (150~180℃) for 40 minutes. Decolorization process: Add a mixed adsorbent of attapulgite (2%) and composite activated carbon (0.8%) to the deacidified oil, stir at 85℃ and a vacuum at 0.08~0.09 MPa for 25 minutes to adsorb pigments and trace impurities; then remove the adsorbent by passing it through a plate and frame filter (filtration pressure 0.4 MPa). Deodorization process: Molecular distillation is used to assist deodorization at 140℃ for 25 minutes, followed by short-path distillation (200℃ / 0.1Pa) for 3 minutes.

[0064] Example 2: Microwave-assisted peanut oil extraction process

[0065] (1) Raw material selection and initial treatment: Select high-quality peanut kernels with an oil content of 50%~55% and a moisture content of 8%~10%, and remove impurities, broken kernels and moldy kernels by vibrating screen (screen hole diameter 2~3mm) to obtain pure peanut raw materials for use.

[0066] (2) Microwave-assisted pretreatment

[0067] Phase a: Microwave frequency 2450MHz, power 280W, processing time 60 seconds.

[0068] Phase b: Microwave frequency 2450MHz, power 320W, processing time 90 seconds.

[0069] Stage C: Aqueous substance: 0.2% (w / v) food-grade citric acid solution; Spraying amount: precisely controlled at 0.4% of the raw material mass; Operation method: uniformly spray using a dual-fluid atomizing nozzle (atomizing particle size 30μm) to ensure peanut surface coverage ≥90%; after spraying, let stand for 30 seconds, maintaining the raw material moisture content at 8%~10% (monitored in real time by an online near-infrared detector; if the content exceeds the standard, it can be finely adjusted for 20~30 seconds with 30~40℃ hot air).

[0070] Stage d: Microwave frequency 2450MHz, power 420W, processing time 80 seconds (microwave 20 seconds interval 5 seconds).

[0071] Stage e: Microwave frequency 2450MHz, power 290W, processing time 30 seconds; after processing, keep warm and stand still for 90 seconds.

[0072] (3) Conditioning and pretreatment: After multi-stage microwave treatment, peanuts are sent to conditioning equipment. The moisture content of peanuts is adjusted to 11%~13% by spray humidification or hot air temperature control, and the temperature is controlled at 40~50℃. The peanuts are kept warm and left to stand for 10~15 minutes.

[0073] (4) High-efficiency pressing: The hydraulic high-efficiency pressing equipment is adopted, with the pressing temperature set at 70℃, the pressing pressure at 15MPa, and the pressing time at 20 minutes.

[0074] (5) Refining

[0075] Degumming process: Add 85% phosphoric acid (0.1% of oil weight) to the crude oil, stir at 50℃ for 30 minutes, and then separate the gums using a disc centrifuge (8000 r / min), with a removal rate ≥95%. Deacidification process: Send the degummed oil into a deacidification tower, control the temperature at 100℃ and the vacuum at 0.09~0.095 MPa, and introduce superheated steam (150~180℃) for 30 minutes. Decolorization process: Add a mixed adsorbent of attapulgite clay (1.5%) and composite activated carbon (0.5%) to the deacidified oil, stir at 80℃ and a vacuum at 0.08~0.09 MPa for 20 minutes to adsorb pigments and trace impurities; then remove the adsorbent by passing it through a plate and frame filter (filtration pressure 0.3 MPa). Deodorization process: Molecular distillation is used to assist deodorization at 130℃ for 20 minutes, followed by short-path distillation (200℃ / 0.1Pa) for 2 minutes.

[0076] Example 3: Microwave-assisted peanut oil extraction process

[0077] (1) Raw material selection and initial treatment: Select high-quality peanut kernels with an oil content of 50%~55% and a moisture content of 8%~10%, and remove impurities, broken kernels and moldy kernels by vibrating screen (screen hole diameter 2~3mm) to obtain pure peanut raw materials for use.

[0078] (2) Microwave-assisted pretreatment

[0079] Phase a: Microwave frequency 2450MHz, power 320W, processing time 90 seconds.

[0080] Phase b: Microwave frequency 2450MHz, power 380W, processing time 120 seconds.

[0081] Stage c: Aqueous substance: 0.5% (w / v) food-grade citric acid solution; Spraying amount: precisely controlled at 0.8% of the raw material mass; Operation method: uniformly spray using a dual-fluid atomizing nozzle (atomizing particle size 50μm) to ensure peanut surface coverage ≥90%; after spraying, let stand for 45 seconds, maintaining the raw material moisture content at 8%~10% (monitored in real time by an online near-infrared detector; if the content exceeds the standard, it can be finely adjusted for 20~30 seconds with 30~40℃ hot air).

[0082] Stage d: Microwave frequency 2450MHz, power 480W, processing time 120 seconds (microwave 20 seconds interval 5 seconds).

[0083] Stage e: Microwave frequency 2450MHz, power 340W, processing time 60 seconds; after processing, keep warm and stand still for 90 seconds.

[0084] (3) Conditioning and pretreatment: After multi-stage microwave treatment, peanuts are sent to conditioning equipment. The moisture content of peanuts is precisely adjusted to 11%~13% by spray humidification or hot air temperature control. The temperature is controlled at 40~50℃ and kept warm for 10~15 minutes.

[0085] (4) High-efficiency pressing: The hydraulic high-efficiency pressing equipment is adopted, with a pressing temperature of 90℃, a pressing pressure of 20MPa, and a pressing time of 30 minutes.

[0086] (5) Refining

[0087] Degumming process: Add 85% phosphoric acid (0.3% of oil weight) to the crude oil, stir at 60℃ for 30 minutes, and then separate the gums using a disc centrifuge (10000 r / min), with a removal rate ≥95%. Deacidification process: Send the degummed oil into a deacidification tower, control the temperature at 120℃ and the vacuum degree at 0.09~0.095MPa, and introduce superheated steam (150~180℃) for 45 minutes. Decolorization process: Add a mixed adsorbent of attapulgite (3%) and composite activated carbon (1%) to the deacidified oil, stir at 90℃ and a vacuum degree of 0.08~0.09MPa for 30 minutes to adsorb pigments and trace impurities; then remove the adsorbent by passing it through a plate and frame filter (filtration pressure 0.5MPa). Deodorization process: Molecular distillation is used to assist deodorization at 150℃ for 30 minutes, followed by short-path distillation (200℃ / 0.1Pa) for 5 minutes.

[0088] Microwave pretreatment experimental design

[0089] Experimental design for verifying the rationality of parameter a in stage 2

[0090] Table 1. Design parameters for the control group in stage a

[0091]

[0092] Experimental Design for Verifying the Rationality of Parameter b in Stage

[0093] Table 2. Design parameters for the control group in phase b

[0094]

[0095] Experimental Design for Verifying the Rationality of Phase c Parameter

[0096] Table 3. Design parameters for the control group in stage c

[0097]

[0098] Experimental Design for Verifying the Rationality of Stage d Parameter

[0099] Table 4. Design parameters for the control group in stage d

[0100]

[0101] Experimental Design for Verifying the Rationality of Stage e-Parameter

[0102] Table 5. Design parameters for the control group in stage e

[0103]

[0104] Methods for testing oil yield by pressing

[0105] The proportion of oil actually obtained after pressing to the total mass of raw materials is calculated by weighing. Record the mass of peanut raw materials after pretreatment (denoted as M, unit kg); press according to the set process, collect crude oil and let it stand for 2 hours; weigh the net mass of crude oil (denoted as m oil, unit kg); calculate: oil yield (%) = (m oil / M) × 100.

[0106] Total phytosterol detection

[0107] The determination of sterol composition and total sterol content in animal and plant oils was carried out in accordance with GB / T 25223-2010.

[0108] Methods for determining vitamin E retention

[0109] High-performance liquid chromatography (HPLC) was used to separate and quantify the total amounts of α, β, γ, and δ-tocopherols in oils. According to the standard GB5009.82-2016 "Determination of Vitamin E in Food", 1.0 g of oil sample was dissolved in 5 mL of n-hexane and filtered through a 0.45 μm organic phase membrane. HPLC conditions: C 18 The chromatographic column (250 mm × 4.6 mm, 5 μm), the mobile phase was methanol-water (98:2), the flow rate was 1.0 mL / min, the column temperature was 30 ℃, and the fluorescence detector (excitation wavelength 290 nm, emission wavelength 330 nm) was used. Quantification was performed using the external standard method: a standard curve was plotted using α-tocopherol standard, and the total vitamin E content (mg / 100 g) was calculated based on the peak area of ​​the sample.

[0110] Experimental results

[0111] Table 6. Detection results of peanut oil in Examples 1-3

[0112]

[0113] As shown in Table 6, the peanut oil obtained by using the microwave-assisted oil pressing process described in this invention in Examples 1-3 exhibits superior performance in terms of oil yield (45.3%~47.5%), phytosterol content (85.0~87.6mg / 100g), and vitamin E retention (49.4~51.2mg / 100g). This indicates that the process can effectively improve the oil yield while better preserving the natural nutrients in peanut oil.

[0114] Table 7. Peanut oil test results for groups A1-1 to A5

[0115]

[0116] As shown in Table 7, when the parameters of stage a in microwave-assisted pretreatment were changed, the pressing oil yield (38.2%~44.2%), phytosterol content (76.4~80.6 mg / 100g), and vitamin E retention (40.2~45.7 mg / 100g) of peanut oil were all lower than the corresponding indicators in Example 1. This indicates that setting the parameters of 280~320W power and 60~90 seconds for stage a plays an important role in improving the oil yield and nutrient retention.

[0117] Table 8. Peanut oil test results for groups A2-1 to A5

[0118]

[0119] Analysis of the control group data in stage b in Table 8 shows that when this stage was omitted or the parameters were broken, the oil yield was only 44.2% at most and the vitamin E retention was as low as 39.7 mg / 100g, both of which were lower than those in Example 1.

[0120] Table 9. Peanut oil test results for groups A3-1 to A5

[0121]

[0122] The experimental results for stage c (citric acid solution spraying) in Table 9 show that if this stage is skipped, or replaced with vitamin C solution, deionized water, or even if the citric acid concentration is simply adjusted to 0.1% or 0.6%, the highest oil yield is only 43.2%, significantly lower than the 47.5% in Example 1. This indicates that the effect of 0.2%~0.5% citric acid solution is specific and cannot be replaced by water or other acids alone; precise control of its concentration and dosage is crucial to improving oil yield efficiency.

[0123] Table 10 Peanut oil test results for groups A4-1 to A5

[0124]

[0125] The control group data for stage d in Table 10 clearly demonstrates the irreplaceable role of this stage: omitting this stage results in an oil yield as low as 37.8%; continuous microwave (without interruptions) or a power increase to 500W drastically reduces vitamin E retention to 34.6-37.9 mg / 100g. This indicates that a power of 420-480W combined with a "20-second microwave, 5-second intermittent" mode effectively breaks down cell walls to release oil while minimizing heat accumulation that damages heat-sensitive nutrients, representing a core design that balances efficiency and nutrition.

[0126] Table 11 Peanut oil test results for groups A5-1 to A5-4

[0127]

[0128] The experimental data for stage e in Table 11 show that when this stage is skipped, the power deviates from 290~340W, or the heat preservation and settling time is reduced to 30 seconds, the oil yield is only 43.5% at most, and the retention of nutrients also decreases accordingly. This reflects that homogenization and stability, by unifying the state of peanut particles (hardness, moisture), provide a uniform physical basis for subsequent conditioning and pressing, and the stability of its parameters is an important prerequisite for ensuring process consistency.

Claims

1. A microwave-assisted peanut oil extraction nutrient retention process, characterized in that, The microwave-assisted peanut oil extraction nutrient retention process includes the following steps: (1) Raw material screening; (2) Microwave frequency 2450MHz auxiliary preprocessing: Phase a: Power 280~320W, 60~90 seconds; Phase b: Power 320~380W, 90~120 seconds; Stage c: Spray 0.2%~0.5% citric acid solution, the amount of which is 0.4%~0.8% of the raw material mass, the atomized particle size is 30~50μm, and let stand for 30~45 seconds; Phase d: Power 420~480W, 80~120 seconds; Stage e: Power 290~340W, 30~60 seconds, keep warm and stand still for 90 seconds; (3) Conditioning and pretreatment: Adjusting the moisture and temperature of peanuts that have undergone microwave-assisted pretreatment; (4) Pressing; (5) Refining.

2. The microwave-assisted peanut oil extraction nutrient retention process according to claim 1, characterized in that, The raw material screening process involves selecting peanut kernels with an oil content of 50% to 55% and a moisture content of 8% to 10%, and removing impurities, broken kernels, and moldy kernels using a vibrating screen.

3. The microwave-assisted peanut oil extraction nutrient retention process according to claim 1, characterized in that, The conditioning pretreatment involves adjusting the moisture content of peanuts to 11%~13%, controlling the temperature at 40~50℃, and keeping them warm for 10~15 minutes.

4. The microwave-assisted peanut oil extraction nutrient retention process according to claim 1, characterized in that, The pressing is carried out using a hydraulic high-efficiency pressing device, with a pressing temperature of 70~90℃, a pressing pressure of 15~20MPa, and a pressing time of 20~30 minutes.

5. The microwave-assisted peanut oil extraction nutrient retention process according to claim 1, characterized in that, The refining process includes degumming, deacidification, decolorization, and deodorization.

6. The microwave-assisted peanut oil extraction nutrient retention process according to claim 1, characterized in that, Phase a is characterized by a power of 300W and a duration of 75 seconds.

7. The microwave-assisted peanut oil extraction nutrient retention process according to claim 1, characterized in that, The b-stage has a power of 350W and lasts for 105 seconds.

8. The microwave-assisted peanut oil extraction nutrient retention process according to claim 1, characterized in that, The c-stage involves spraying a 0.35% citric acid solution at a rate of 0.6% of the raw material mass, with an atomized particle size of 40 μm, followed by a standing time of 40 seconds.

9. The microwave-assisted peanut oil extraction nutrient retention process according to claim 1, characterized in that, The d-stage has a power of 450W and lasts for 100 seconds.

10. The microwave-assisted peanut oil extraction nutrient retention process according to claim 1, characterized in that, The e-stage has a power of 320W, a duration of 45 seconds, and a heat preservation period of 90 seconds.

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